Fluid piston pump



Jan. 13, 1942. B. F. scHMlDT FLUID PISTON PUMP Filed Sept. 28, 195'] 6 Sheets-Sheet l Jan. l13, 1942. B. F. SCHMIDT 2,269,789

FLUID PISTON PUMP Filed Sept. 28, 1937 6 Sheets-Sheet 2 l l l INV ENT OR. f/A/m/ ffm/war BY l (44 ATTORNEY.

Jan. 13, 1942.

B. F. SCHMIDT FLUID PISTON PUMP Filed sept. 28, 1937 e sheets-sheet 4 ATTORNEY,

Jam 13 1942- B. F. scHMlDT l 2,269,789

FLUID PI STON PUMP ATTORNEY.

Patented Jan. 13, 1942 UNirED STATES PATENT OFFICE '28 Claims.

My invention relates to a type of pump particularly adapted for deep well pumping in which a mobile liquid is utilized as the active pumping medium, that is, it provides a fluid piston which in the rise and fall causes the upward pumping of the liquid from the well. In this type of pump the liquid piston must be of such a character that it does not deteriorate when brought int-o contact with the liquid in the Well or with abrasive or gritty materialor other foreign matter which is carried as a mixture in the well liquid. As my invention is particularly adapted for pumping deep oil wells, I prefer to use mercury as the pumping liquid tg form the fluid piston. The mercury is not contaminated by the oil or by sand, the gases or other foreign materials in the oil. I find it also advisable in my pumps t-o have the surfaces which are alternately in contact with the well oil and the mercury silver plated as this facilitates themercury cutting or removing any adherent oil or materials from the metal parts of the pump with which the mercury may contact.

One of the main objects and features of my invention in this type of a uid loperated pump is in providing a plurality of pump chambers to contain the mercury acting as the pistons and the oil to be pumped. The mercury is pumped from one chamber to another and as the volume of mercury in one chamber is depleted, oil is drawn in fto such chamberI by suction or the pressure in the well. The mercury pumped out of one chamber is forced into` another, thereby expelling the oil from such latter chamber which oil is conveyed upwardly by any suitable type of piping.

A further object and feature of my invention in this type of pump is having a continuous pumping action on the mercury Ias by means of a'continuously acting mechanical pump of a construction which may develop a high pressure, and in conjunction with the mechanical pump I employ a rotary valve which develops a, re-

verse flow of mercury from one pumping chamber tothe other and then back again as a column of oil is forced `upwardly through the assembly. However in a iiuid piston pump employing a plurality of chambers operating in the manner described, it is sometimes diicult to prevent one chamber being completely exhausted of the mercury. This may be due to irregularities in the conduits or such like for transferring the mercury from one chamber to another or by more or less accumulation, of gas in one or both of the chambers. As such gas is compressible it may cause one chamber to be depleted of mercury, that is, the fluid piston, while the other chamber has an excess. of mercury.

Therefore another feature of my invention relates to a float stop valve construction operated by the column of mercury in each chamber so that when the mercury is depleted to a predetermined amount, the outflow valve of the mercury from such chamber is closed. At substantially the sa'me time the rotary valve occupies a position so that the mercury in the chamber having av surplus quantity is transferred to the chamber having the depleted volume of mercury'and thus again equalizes the amount of mercury requisite for the proper pumping in both chambers. The shut-o valve for each mercury chamber is preferably of a iioat type in which normally the valve is floated in the body of mercury but on depletion the valve drops to a seat, thus making a closure against the outflow of mercury from the particular chamber. For sake of simplicity of construction, for deep well pumping I preferably provide two elongated chambers each substantially semi-cylindrical and constructed in a cylindrical housing accommodated in the bore ofy the well, or the well casing.

Another object and feature of my invention in a submerged pump includes the feature of lowering the whole assembly, preferably by a cable or the like and having the power unit or motor positioned deep in the well and contiguous to the pump proper. In this connection I preferably use an electric motor and illustrate this in the'drawings, -but it is to be understood that other types of motors such as liquid operated or air motors might be utilized. However, with the electric motor the suspension cable for lowering the equipment into the well is constructed to house the conducting cables for the electric motor.- Y

A further object and feature of my invention therefore is in employing a motor in a deep well pump and having this operate a vertical shaft which drives the mechanical pump. Such mechanical pump is at the bottom of the pump assembly and may be vof any suitable type, however I prefer to include a system of reduction f' gears to reduce the high speed necessary for an electric motor to a low speed suitable for a rotary valve operated with said pump. Therefore as the electric motor and the gear reduction equipment must be under high hydraulic pressure due to the pressure of the oil-in -the well, another feature of my invention includes liquid baille-connections from, for instance, the interior of the motor to the oil of the well so that the motor as to the inside and outside pressure is equalized with the hydraulic head in the well. Likewise in the reduction gear train, by providing that this operate in an oil bath and the shaft also be surrounded by oil with pressure connections to the oil of the well, it is not necessary to have expensive or pressure tight pack; ings to prevent entrance of the well oil. f

My pump may be mounted in a well in various suitable ways such as by employing a packer type of shoulder in a well casing and providing the upper end of the pump assembly with a head block which may rest on a packing type of shoulder. This head block is provided with apassage for the upward ow of the well liquid such as oil. If desired the ,.'oil may be carried upwardly in the well casing in which instance it is desirable to have a relief valve in the head block with a check valve connected to the lifting and lowering cable which cable also encloses the electric conducting cable. Such check valve prevents the downow of oil but when it is desired to lift the assembly the upward pull on the lifting cable 'opens the check 4valve to release part of the oil in the upper part of the casing to equalize the pressure immediately above and below the packing shoulder. By another form of construction I may run a small bore string of oil tubing from the head blockto the top of the well, this being useful in conditions in which the casing does not runto the well surface. In another form of construction I may employ a well tubing connected directly to the head block of the pump assembly with the hoisting and lowering cable passing centrally through this oil tubing, then by means of an offset fitting, a string of oil tubing is carried up parallel to the cable. With this arrangement it is desirable to employ a sleeve-like head having a loose fit on the lower part of the oil tubing and provided With a head engaging the packing shoulder. 'I'his sleeve by means of a flare supports the ilared upper end of the lower part of the Aol tubing, thus suspending the pump assembly in the well and allowing for readily lowering and lifting this whole assembly. Where the pump assembly is supported on a packer type of shoulder my invention comprehends not only the 'release of any oil accumulating above the head block or sleeve-like head, but the release of any sand which may so accumulate on the initial movement to lift the pumping assembly in the well. desirable to release vany sand or oil which accumulates above the packer and this may be done by slightly lifting the pumping assembly which allows all of the sand with the oil to flow downwardly to the bottom of the well and thus prevents freezing the pump in the well,

My invention also includes a construction and mode of operaton in which the so-called fluid piston includes a clean liquid` such as oil which may be operated through the pump and this acts on the piston liquid which is insoluble in the liquid being pumped. Such insoluble liquid is preferably mercury and when the pump chambers are plated in a suitable manner, the mercury operates to clean any sticky or gritty material in the well liquid from such finished surface. In this case of pumping a clean and relatively light weight liquid, such clean liquid forms with the mechanical pump an actuating means for the insoluble fluid. My invention also comprehends a construction by which the motor, the pump and reduced speed gear, together with the main valve operating withthe pump may be located above the intake for the well iluid through the well liquid and above the chambers' for the insoluble fluid piston. However if desired the electrical and mechanical equipment may be separated by the location of the chambers for the uid piston and for the ilow of the well liquid. My invention also, comprehends a construction and operation in which the well In case of a shut down it is often` liquid is drawn in and pumped upwardly from a single chamber -in which case it is necessary to use a chamber or reservoir for the storing and flowing of the pumping fluid on the suction or discharge strokes.

My invention is illustrated in connection with the accompanying drawings, in which:

Fig. 1 is a vertical section of the lower part of a-well illustrating the pump assembly housing in apartial section and interior parts of the pump assembly mainly in elevation.

Fig. 2 is a vertical section through the lower part of a well showing an alternative construction for supporting the pump assembly.

Fig. 3 is a detail elevation of the upper part of Fig. 1 to illustrate the operation of a relief valve used when withdrawing the pump from the well.

Figs. 4 and 5 are connected vertical sections through the pmp of Fig. 1 shown on a larger scale and may be considered as taken on the sec tion line 4-5 of Figs. 6 and 8 in the direction of the arrows.

Fig. 6 is a transverse section on the line 6-6 of Fig. 5 in the direction of the arrows.

Fig. 7 is a transverse section on the line 'I- of Fig. 5 in the direction of the arrows.

Fig. 8 is a transverse section on the line 8-8 of Fig. 5 in the direction of the arrows.

Fig. 9 is a section similar to Fig. 8 with the rotary valve in a second position.

Fig. ,10 is a section similar to Figs. 8 and 9 with the rotary valve in a third position.

Fig. 11 is an enlarged vertical section 'on the irregular line ||.l I of Fig. 6 taken in the direction of the arrows.

Fig. 12 is a section similar to Figs. 8 and 9 showing the valve in another position.

Fig. 13 is an elevation broken away of the lower portion of the well showing the passages connecting the pump and the valve.

Fig. 14 is a section similar to Figs. 8 through 12 with the yvalve removed illustrating the ports connecting to the pump.

Fig. 15 is a vertical section of part of the pump illustrating a single chamber piston pump, such figure may be considered a modication of a portion of the section shown in Fig. 1.

Fig. 16 is a vertical section of a modification of the construction of Fig. 1 in which additional chambers are used for the yliquid piston and in which a clean oil or the like is actuated by the mechanical pump instead of the mercury and this clean oil develops a rise and fall of the mercury in the piston chambers. This may be considered as a section somewhat similar to Fig. 1.

Figs. 17 and 18 are upper and lower sections of a further modification of the pump in which the motor, the gear reduction train and the pump are located in an upper position of the assembly, the piston pump chambers being located adjacent the bottom and reservoirs for the iluid 5 in this' a well casing or well bore is indicated by internal valve support 2|.

the numeral I having a packing or other supporting shoulder 2. The submerged pump assembly 3 has a cylindrical casing or housing 4 in which a motor 5 is located at the top. Below the motor there is an oil pressure equalizing assembly 6. The shaft assembly 1 extends through the uid pump chamber assembly 8 and drives a speed reduction gear' assembly 9, this latter being operative to actuate a rotary valve hereunder described. The-pump I8 is illustrated as having a direct drive for shaft 1 but a gear reduction may be used. y

Dealing rst with the main characteristics of the fluid or liquid pumping and its Achamber designated by the assembly numeral 8, the housing assembly 3 having the casing 4 employs as part of this casing a lower or preferably cast fabricated pump structure I5 which at its upper end has an internal threaded coupling |6 provided with an annular rim |1 having a threaded connection to the upper part of a cast or fabricated pump housing I8. This housing is cylindrical onv its outside and is provided with an upper internal shoulder I9, a lowerY internal shoulder 26, these being formed in a thickened At the lower part there is a solid block or base 25 with a recess 26 therein and a cylindrical bore 21, this also terminating at its lower end in a packing recess 28. A shaft casing tube 29 is seated in the recess 26 and is preferably either cast therein or fabricated. A diametrical partition or web 30 connects the outside wall I8 and the shaft casing tube 29 (note Fig. 6). This structure may be fabricated or cast. The shaft casing tube 29 and the webs 38 terminate at the level of the lower shoulder 20, note Fig. 4.' There are thus dened two liquid chambers 36 and 31 on opposite sides of the partition 30 having a bottom surface 38 forming the upper part of the block section 25. A closure plate 39 seated on the shoulder 28 and on the upper end of the casing tube 29 and the webs 39 form the upper limit of the liquid or fluid space. properly seated and provided with suitable packing 40 forming a liquid tight joint atthe Shoulder 28, the upper edges of the partition 38, and the -circular upper edge of the casing tube 29. This plate 39 has studs or pins 4| extending upwardly to engage in complementary sockets in a valve block assembly hereunder detailed.

This plate 39 is Dealing next with the portions of the pump functioning directly with the ow of the well oil, at the bottom ofeach of the pump chambers 36 and 31, there are two oil intake valve assemblies designated respectively. 45 and 46.' These are of the same type and each has a tube or pipe 41 having a threaded connection to the block 25 as indicated at 48 and, below this,

sloping oil inlet ducts 49 and 56 communicate with .the exterior of the block 25. It will be noted that there is an annular space for-the upiiow of oil between the submerged pump assembly and the well casing I. Check valves 52 are secured to the upper ends of the pipes 41, these being illustrated as having a cage 53 threaded on the upper ends of the pipe and retaining a valve seat ring 54 in place upon which seats the ball 55. The-cages' are illusi'ated-as slotted. These check valves therefore allow upward flow of the well oil but prevent the downward ow.

The upper oil valve assembly (note particularly Fig. 4) employs'a valve block 6| which has its lower end bearing directly on the plate 39,

there being sockets to accommodate the studs or pins 4| and thus permit accurate centering of this block. Such block has a bore 62 through which extends an uppershaft casing tube 63, this having a threaded connection'64 to the lower casing tube 29. A packing 65 and packing gland 66 form a leak-tight joint.

The port and outlet valves consist of a pair of ports 10 in the closure plate 39 which register with two ports 1| in the block 6|. This block has two threaded recesses 12 in which is threaded the outlet valve cage tube 13, this seating on a seating ring 14 upon which rests a ball 15. A transverse pin 16 limits the upward movement of the ball and the edge of thecage tubes is slotted, thus giving adequate area for outow of the oil. The coupling I6 is operative to retain the valve block 6| and its assembled parts in position.

The lower portion of the liquid chambers 36 and 31 forms a space for the liquid piston and, as above described, for pumping oil I find that mercury is the most satisfactory liquid forthis purpose. The pump III therefore is a mercury pump receiving its supply from one of the chambers 36 and discharging into the other, the action being in an alternate manner controlled by a valve. Such construction is detailed hereunder. Extending downwardly from the block 25 is a combination gear housing assembly 88 with the pump housing 8| therebelow. The gear housing includes an internal cylinder 82 connected to the outer cylinder housing 83, there being illustrated four radial connecting webs 85, note Figs. 1 through l0. Thesedefine therefore four segmental spaces 86, 81, 88 and 89. The upper ends of these spaces lead to diagonal passages 9I| and Y90', note Fig. 5, which converge inwardly to two ports in the bottom of the chambers 36 and 31, thus from the space 86 there is an inlet port 9| (note Fig. 6) and from the space 81 there is an inlet port, 92, from the-space 88 there is' an outlet port valve assembly 93 and from the space 89, an outlet port valve assembly 94.

The valve assemblies 93 and 94 each have a iioatvalve assembly including a valve seat ring `having a guide opening for the oat valve |0I.

Each of these valves has a rod |62 slidable through the opening at thebottom with a ball type valve .plug |03 to engage the seat 96. AV float head |84 is secured to the top of each rod. These oat valves may be made of metal of such a specific gravity that they will float in mercury. v The shaft assembly 1 leading from the motor 5 has alower or driving end 0 which passes through the block 25, there being a sealing packing III located inside the lower portion of the shaftcasing 29. The packing recess 28 is provided with packing |I2 (note Fig. 5), this being held in place by a slip gland I|3. A compression spring ||4 bears against this gland and thrusts against'a bridging plate I5 secured at ||6 to the lower surface ||1 of the block 25. In the space defined by the internal cylinder 82 and thisbottom surface ||1, there is located a reduction gear train |20 consisting of a series of planetary gears of which the main driving gear |2| (note Fig. 5) is secured by a key |22' cr the being the stationary ring gear |21 meshing with the planetary or pinion gears. The sequence of gears is built up in the same manner, the shaft having a bushing |28 on which the hub gearsrotate. In this manner a speed reduction is communicated to a slow speed valve block designated by the numeral |35, the last set of studs |36 of the gear train carrying the last set of pinions |31 being secured to this valve block. Such block has a series of sealing rings |38 engaging the inside cylinder 82 and is provided with a packing recess |39 in which there is compressible packing |48l held in place by a slip gland |4| by a compression spring |42, This spring engages threaded clamping rings |43 (note Fig. 5) which are held in place by the pump block |50,

this being dened as having an upper surface l the lower ends |52 of the inner cylinder 82 being seated therein with suitable packing or connections to be proof against the leak of mercury. There is also a packing |53 between the lower part of the valveblock |35 and the upper surface |5| of the pump block |50. This pump block is held in place by a threaded plug |55 threaded in the lower end of the pump housing 8| I do not illustrate the details of the mercury pump as there are a number of types of rotary pumps f which may be used for this purpose and if one pump cannot develop sufficient pressure, two

pumps, one above the other may be intercon nected to develop suflicient pressure in the mercury pumped to and fro in the chambers 36 and 31.

The mercury-pump has two passages indicated at |60 and |8| which lead upwardly and each is dividedV having two branch arms |62 and |83 which lead to ports |64 and |65 which in the present drawings may be considered as inlet ports to the mercury pump conducting the mercury downwardly from the oil chamber having the mercury piston to such mercury pump. At the mercury pump the branches |62 and |63 lead to ports |86 and |61 which may be considered as providing for the forced upward flow of mercury from the mercury pump to the oil chamber to raise the level of the mercury in the fluid pump for' upward discharge of the oil. All of these pbrts |64, |65, |66-and |61 are concentric with the valve block |35 and hence with the drive shaft |||Jl and are spaced inwardly and aligned with the vertical mercury flow slots |68 and |69 in the valve block |35. nected at the top with radial slots and |1| of the valve block |35, these slots leading to the internal cylinder 82.

This cylinder is provided with a series of ports, the port communicating with the segmental space 86, the port |16 with the space 81, the port |11 with the space 88 and the port '|18 with the At the upper end of the segmental space 89. spaces 88 and 39, there are upwardly extending passages |80 and |8| communicating respectively with the outlet float valve ports 93 and 94 from the fluid piston chamber (note Fig. l1). From the segmental spaces 86 and 81, there are also the upwardly inclined passages 90 and 80', note Fig; 5, leading respectively to the inlet ports 8| and 92 of the fluid pump.

As above mentioned the valve block rotates at a relatively slow speed and this is indicated as being in the direction of the arrow |85 (note Figs. 8, `9 and 10). Presuming the valve block These latter are con- |35 ls in the position shown in Fig. 8, then mercury is being drawn out of the chamber 36 through the outlet valve 94, crossed downwardly through the passage |8| to the space 89, inwardly through the port |18 through the aligned radial slot |10 of the valve block |35, downwardly through the passage |68 and thence through the port |65 which forms an inlet to the mercury pump in the lower part of the assembly. From this pump the mercury lis forced upwardly through the port |61, the passage |68, the slot |1|, the port |16 to the lower part of the space 81 and thence upwardly through this space, the inclined passage 90 and by the inlet 92 flows into the chamber 31. It will thus be seen that the pump at this stage has its inlet or supply from the chamber 36, thus lowering the mercury piston in such chamber and forcing the mercury into the chamber 31. The direction of flow of the mercury through the ports |16 and |18 is indicated respectively by the arrows |86 and arrows |81.

In the stage of rotation of the valve block |35 illustrated in Fig. 9, the outlet valve 83 of the mercury chamber 31 forms the downflow inlet to the mercury pump. The iiow is thus downwardly through the inclined passage (note Fig. 11), the segmental space 88, the port |11, the valve slot |1| communicating by the vertical passage |88 with the port |64, thus supplying mercury to the pump, the direction of flow through the port |11 being indicated by the arrow |88. The mercury forced upward by the mercury pump has its outlet through the pump port |66 and flows upwardly through the passage |68 of the valve block 35, the slot 10, the port |15, to the segment 68, the direction of ow through the port |15 being indicated by the arrow |89. The flow is then upwardly through this segment 86, the inclined passage 90 to the inlet port 9| of the iiuid piston chamber 36, thus replenishing the mercury in suchchamber and raising its level while it flows downwardly and outwardly from the chamber 31. will be seen that by the flow of mercury into and out of the iluid piston portion of the pump that this only flows in a downward direction in the segmental spaces 88 and 89 from the outlet valves 93 and 84. Also the flow is only in an upward direction in the segmental spaces 86 and 81 discharging through the ports 9| and 92 into the chambers 36 and 31. Therefore there is only an inward ow through the ports |11 and |18 from the spaces 88 and 89 and only an out ow through the ports |15 and |16 to the spaces 86 and 81.

As above mentioned, it may happen sometimes that the mercury in one of the chambers either 36 or 31 will be exhausted t0 too low a level and in which case one or other of the float valves |0| will seat. This action is illustrated in Fig. 11 in which the oat valve communicating with the chamber 36 is shown in the seated position, that is, the ball plug |03 is seated on the seating ring 95. During the relative ,slow rotation of the valve block |35 this condition becomes rectified. For instance when the valve block is in the position shown in Fig. 10, both of the parts |64 and y| communicating from the oil chamber, that is, the iiuid piston chambers to the power pump are open and the two ports |66 and |61 through which the mercury is forced from the power pump upwardly are also open and, as above mentioned, as the mercury can only flow downwardly in the spaces 88 and 89 and the oat valve 84 leading Therefore it cf its outlet valve.

a back ow of oil to the well.

to the space 89 is closed as shown in Fig. 11, all of the mercury to provide for the operation of the power pump is drawn from the over-full chamber 31 through the float port outlet 93. On aecount of the ports |66 and |61 also being both open at the same time, the mercury is forced upwardly by the power pump through the spaces 86 and 81, the ports 9| and 92, to the chambers 36 and 31.A Therefore these chambers receive a supply of mercury and as it cannot float out of the chamber 36, the valve 94 being closed, the mercury level is raised. AIn addition due to the differential hydraulic head in the chambers 36 and 31, there is a greater back pressure in the chamber 31 to the replenishing flow of the mercury, hence .most of the mercury pumped from the chamber 31 through the space 88 and the port |64 is replenished to the chamber 36, thus equalizing the mercury in the two chambers sothat in the normal operation the valves 93 and 94 do not close unless of course there is some irregularity to the ow of mercury downwardly to the mechanical pump and upwardly from such pump in one of the lines of communication. An

irregularity in the ow of mercury may be gas accumulating in the pumping chambers, such gas separati-ng from the well oil and hence as such gas would be compressiole, it might cause an ir, regular flow of the mercury and too great a depletion of-V one chamber.

In view of the fact that the mechanical pump is always operating, it is necessary to provide for a continued flow of mercury from one or other of the spaces 36 and 31 or both and back to one .or both of these chambers. When the valve block of the movement of the valve block |35 being comparatively slow, there does not develop a quick and decided shut off or opening of any particular c annel of flow of the mercury and hence there is no elect developed similar to a'water hammer or ,the like. f f

The ow of oil from the well is developed and controlled by the action of the fluid mercury 7 pump. Hence for instance as the mercury drops in the chamber 36 oil is forced into this chamber by the hydraulic'pressure in the well, the outlet valve connecting with such chamber being closed by the oil thereabove. This inlet of oil to the chamber 36 is through the inlet duct 49 and the valve 45. The upwardly moving fluid piston developed by the rise in the level of mercury in the chamber 31 forces the oil in this chamber above ithe mercury upwardly and out The back pressure against the valve 46 in seating the ball valve prevents There is thus a repeated cycle of the inlet of oil to, say, chamber 36. the elevation of such oil. then the forcing of the oil upwardly from the chamber 3S while it is being replenished in the chamber 31, such cycle repeating.

The flow of oil in the construction shown in Figs. l. 3 and 4 from the uid piston, that is.

the mercury pump, includes as an oil float space,

the chamber 200 inside of the upper part of the casing 4. This is an annular space surrounding the upper shaft casing tube'63, the space 20| surrounding a baille balance 6 described hereunder in detail and also surrounding the motor 5. This motor is attached to the housing l4 by a motor support plate 202, this vhaving a series of channels or perforations 203 for the upward flow of the oil.

The suspension of the pump in the well by the equipment of Figs. 1, 3 and 4 includes the packer or supporting shoulder 2, ahead block 2|0 which has a threaded connection 2|| to the upper part of the housing' 4 and is provided with annular shoulders 2|2 seating on the conical upper end of the packer or supporting shoulder 2. There is an oil outlet passagel2|3 through the head 2|| and through an oil pipe 2|4 made up in stands and leading to the top of the well. This is shown vas. having a screw threaded connection to the rim 2|5.

The combined electrical conducting and lifting and lowering cable 220 by which the whole of the pump is lowered into the well and lifted passes throughan opening 22| in the head 2|0, the head being provided with a recess 222 having a packing 223 and a packing gland 224,

thus making an oil tight connection. There isy a clamp or other attaching. device 225 connecting the lower end of the cable to the plate 202 with the conducting leads to the motor. y

The oil pressure equalizing assembly 6 which may be considered as a baille oil balance, equalizes the internal pressure in the motor by bringing oil inside the motor under the same hydraulic head as the oil being pumped upwardly through the spaces and chambers 200 and 20| and thence to the top of the Well. The shaft assembly designated by the numeral 1 has a motor shaft 230 (note Fig. 4) which extends downwardly through an anti-friction bearing 23| mounted in the motor and engaging a lower motor head 232, this head having a shoulder 233. An internal sleeve -234 is shown as formed integral with the head 232 and extends downwardly to a 'an upper end closure 24| and a lower similar closure 242 engaging between the heads 232 and the ring 235 and being secured by a packing to be oil tight. A series of openings or perforations 245 shown in the closure 242 communicate with the outer annular space 246. .Passages 241 at the top of the sleeve` 238 communicate with the annular space 248. A series of perforations 249v at 'the lower part-of the sleeve 238 communicate with the, space 250 and a series of upper perforations or ports 25| communicate through the sleeve-234 to the inner chamber 252. When all of these spaces and chambers are filled with clean oil and clean oil is filled in the space 200 and 20| before the pump assembly is lowered into the well, it will thus be seen that the balance baille due to the intricate channels which would be required for the inflow or outflow of oil, mainv tain this clean oil developing an internal preswashed out by the upward flow of well oil and there is practically no intermingling. This cleanv -oil also lls the annular space between the various sections of the pump 8 extending downwardly in the various sections of the shaft housing.

In the construction shown in Figs. 1, 4, and 5, I illustrate the oil pipe 2 |4 as extending upwardly in the well. If the well casing is tight it is not necessary to continue this pipe to the top of the well. In fact, it may be omitted entirely and the oil flowed upwardly in the casing from the oil outlet passage 2|3 in the head block 2|0. It is usual to have a liquid-tight seal by means of the packing at the joint formed by the annular shoulders 2|2 and the supporting shoulder 2. If the oil is pumped upwardly in the well casing, omitting the oil pipe 2| 4 or even when this pipe is used on account of the possibility of there being a head of oil or other liquid on the head block 2|0, it is desirable to have an equalizing valve construction which may be opened to drain liquid from above the head 2|0 to a portionY of the well below the supporting shoulder 2. Such a relief valve assembly is illustrated in Figs. 1 and 3, certain details being shown in Fig. 4, this being designated by the assembly numeralv 260. This includes the head block 2|0 having a vertical bore 26| leading downwardly from a threaded rim 262. A closure plug 263 blocks the bottom of this bore and from the bore there is a lateral passage 264 in the head block leading through an opening 265 in the upper end of the cylindrical casing4. This communicates with an annular space 266 inside of the shoulder 2. A valve tube 261 leads upwardly from the rim 262 to which it is connected and has a check valve 210 at its upper end. This check valve includes a seat 21 I. On the upper end of the tube 261 a perforated cage 212, a. ball 213 mounted in the cage and having a stem 214 connected with the ball and operating through a bearing in the top of the cage. A compression-seating spring 215 normally maintains the ball seated. A pull cable 216 is connected to the upper end of the stem 214 and attached to a clamp 211 which is secured to the main cable 220.

When the pump assembly is being lowered into the well, this main cable is tau't and hence the pull cable lifts the ball off its seat. However, when the head 2 I0 rests and is supported onthe shoulder 2, the spring 215 seats the ball and thus closes the valve 210 and this remains closed in the normal operation of the pump, and thus, if the well oil is pumped upwardly in the casing or if the oil pipes 2|4 are disconnected so that the oil or other well liquid develops aconsiderable hydraulic pressure on the head 2|0, then this valve may be opened when it is desired to lift the pump assembly from the well. In this action the upward pull on the main cable 220 through the medium of the clamp 211 exerts a pull on the short cable 216, thus lifting the ball from its seat and allowing any liquid above the head 2|0 to flow downwardly through the bore 26| to the passages 264, 265, and 266 to the section below the well to the shoulder 2 and thus equalizes the pressure above and below the head 2|0, allowing ready removal of the whole pump assembly. It will be noted there is sufllcient clearance inside of the shoulder 2 for lowering and setting the pump for again' lifting it to the `surface of the well.

l In Fig. 2 I show an alternative construction for mounting the pump in a well necessitating a slight change in the upper part of the pump assembly. For instance, instead of the head block 2|0 I substitute a head block 300 connected to the upper part of the housing 4 by a screw threaded connection and this head has a central opening 30| for the upward flow of oil and to form a passage for the lifting and conducting cable. Where this cable passes through the head block I employ packing and a packing gland somewhat in accordance with the construction of Fig. 4. An oil tube or pipe 302 is attached to the head block 300 preferably by welding, the inside aligning with the opening 30|. This tube has a flared upper end 303 with a threaded rim 304 extending thereabove. A tubular oil fitting 3|0 has a cylindrical lower part 3|| having a threaded connection to the rim 304 and is provided with a perforation 3|2 for the cable 220, there being a recess 3|3 in which is fitted a compressible packing 3|4 held in place by a gland 3|5 forming an oil tight connection with the cable. An offset tube 3|6 is threaded at its upper end 3 I1 and to this is connected a string of oil tubing 3|8 which may lead to the top of the well. This tubing has clamps 3I9 connected to the cables at various stands to prevent the cable and the pipe becoming tangled. In order to support the pump assembly on the supporting shoulder 2 I employ a substantial sleeve head 325. This has a. cylindrical section 326 and an enlarged head 321, such head having a bevel 328 engaging the upper surface of the shoulder 2. The head has a beveled surface 329 engaging the flared upper end 303 of the oil tube 302. The central bore 330 is of sufficient diameter to give a clearance for the tube 302. With this construction as the assembly is being lowered in the well the head sleeve 325 rests on the head block 300 until there is an engagement with the shoulder 2. The pump assembly is then lowered until the pump is supported by the flared upper end 303. The oil or other well liquid is pumped upwardly past the motor through .the oil tube 302, the fitting 3|0 and the string of oil tubing 3|8. In this case it is not necessary to have any relief valve as the weight of oil or other well liquid on the sleeve block .325 is insufficient to prevent the upward lift of the pump assembly breaking the joint with the shoulder 2. In both the construction of Figs. 1, 4 and 2 it is preferable to have a compressible packing at the contact upper surface of the shoulder 2 as is common practice in oil well and similar constructions.

In Fig. 15 I show a modification of the construction of Fig. 1 in which I employ one pumping chamber 350 and one reservoir chamber 35|. These may be the same shape and contour as shown in connection with Fig. 1 except that there is only one intake passage 49. Thus the reservoir chamber 35| has a closed bottom 352 except for the ports for the in and out, flow of mercury. The valvefblock 355 is also modified by having only one outlet valve assembly 356. Otherwise the construction is substantially the same as illustrated and used in connection with Fig. 1 and associated figures.

In the operation of the single chamber fluid piston on the suction stroke in which the well oil flows in through the inlet duct 49, the mercury is withdrawn from the pumping chamber 350 and is charged into the reservoir chamber 35|. When assembling the pump before lowering in the well. it is desirable to fill the reservoir chamber 35| with mercury or else to have only a small volume adequate volume of mercury to be lled into the reservoir 35|. On the lifting stroke the mercury is pumped from the reservoir 35| into the piston chamber 358 and forces the oil trapped therein upwardly through the outlet valve 356. By using thisconstruction of a single fluid piston chamber, such chamber may be made of considerable length and in fact the reservoir 35| and the pump chamber 358 are not necessarily on the same level but may be positioned in different parts of the pump assembly.

The construction of Fig. 16 illustrates in vertical section the equipment for using a'cleanroil or similar. 'liquid actuated by the mechanical pump and this clean oil develops the mercury flow. By such construction the mercury never contacts the mechanical pump and the clean oil entering and being discharged from the me chanical pump never comes in contact with the well oil. In this arrangement I employ piston pump chambers 315 and 316 of the same type as shown in connection'with Fig. 1, these being divided by a Vertical partition 311. The bottom of each chamber is formed by a base block 318 having substantially the same structure and function as the base block-25 of Fig. 1. 'I'hrough this block there are two inlet oil passages 319V and 388 leading to oil inlet tubes 38| and 382, each having a standing valve assembly 383 to allow the inflow but check the back ow of oil.

Below the block 318 I employ the double shell structure 385 having the outer casing 386 and the inner cylinder 381 spaced therefrom and forming a series of vertical segmental passages 388 theequivalent of the segmental passages 86, 81, 88 and 89. These lead downwardly to the rotary valve |35. There are two reservoir chambers 389 and 398 separated by a continuation of the partition 311 and terminating at the bottom block` 39|. There are ports indicated as 392 leading from each4 of these reservoir chambers to the segmental passages 388. The outlet connection for the mercury from each, of. the chambers 315 and 316 includes an outlet tube 488 which extends through the block 318 and has a valve seat 48| thereon. The lower end 482 of each of these pipes is open and positioned spaced slightly above the bottom block 39|. Af float valve assembly 483 consists of a guide 484 through which operates the valve rod 485, this having a ball 486 to engage the seat 48| and a float 481, the oper` ating function being the same described in connection with the float valve 94. By this construction there is therefore the active fluid piston indicated by the mercury 4|8 in." the chambers 315 and -316 and the mercury column 4|| in each of the ow tubes 488. In this case there is only the single tube connection from the upper pumping chambers to the reservoir chambers provida column indicated at 4| I, thus raising the mercury level in the pump chamber 316 and forcing the well oil upwardly from said chamber. The action is substantially the same as described in connection with Fig. 1 and associated drawingsv except that in this case the mechanical pump and thevalve |35 operate on the clean oilor similar liquid and this liquid directly actuates the mercury of the fluid piston. By such construction the mercury does notl enter the mechanical pump and the clean oil is kept spaced and distinct from the well oil.

The construction of Figs. 17 through 20 employs a clean liquid such as oil actuated bythe mechanical pump and operative to displace the mercury.` As such latter forms a fluid which is insoluble both in the pumping oil and the well oil, themercury forms the active element of. a fluid piston. 1 This construction changes the position of certain of the mechanical elements from that of the prior described illustrations. In such` arrangement I employ a cylindrical casing or housing 458 which is similar in character to the element 4 of Fig. 1 and may be connected to a head block or the like. The electric motor is supported in an upper part of the housing and operates thedrive shaft 452. The equalizer baille as- I-sembiy 453 is located below the motor and bolted of well liquid from the circular or segmental ing for the up and down flow of the mercury by .X

means of the column 4| I. There is always a body of mercury 4|2 in the reservoir chambers 389 and 398. The clean oil or other liquid occupies the space 4|3 .above the mercury level in the reservoirs 389 and 398, and the passages 388 to the valve block |35 and hence to the pump.

The operationv of the construction of Fig. 16 is substantially as follows: In this case the mechanical pump plus the clean oil which flows through suchpump through the valve |35 may be considered as the activating means for the mercury piston. On the intake stroke for the well oil, for instance into the chamber 315, the clean spaces 459 between the casing 458 and the internal cylinder 451. The gear reduction train designated 468 is mounted in the cylinder 451' and driven by the shaft 452.

internal cylinder 451 terminates at an upper boltnection 41| to the casing 458. The upper surface 412 forms a ported valve seat, note particularly Figs. 19 and 20. This is provided with four ports, 413, 414, 415 and 416, each port extending through the block. In addition such block is provided `with a series of passages 488 communicating at the top with the space for passage for well liquid designated 459. Bolts 48| extend through the block 418 and secure the pump in place preventing its rotation.

In this construction the rotary valve 485 has a cylinder or cage construction 486 surrounding the sides of the pump 465 and having an upper head 481 connected to the last slow speed `drive of the reduction gear train, there being a central oning 488 for the passage of the lower end 46| of the shaft 452. The sleeve 486 is preferably internally threaded as indicated at 489 in which is fitted a bolted valve ring 498. Such ring has two segmental ports 49| and 492. These are formed of slots extending through the valve ring from the top to the bottom and concentric with the axis of the valve and positioned to cover The lower end 46| of such shaft'is connected to and operates; the pump designated by the assembly 465. The

and uncover the ports 413, 414, 415 and 416. This ring thus engages the upper seating surface 412 of the block 410. The pump may be the same as described in connection with Fig. 1 except that the passages and ports of the pump are reversed and extend downwardly instead of upwardly.

A reservoir section 500, note Fig. 18, has an outside cylindrical wall 50| preferably the same size as the cylinder casing 450. It is provided with an upper closure head 502 and a lower closure head 503. The upper head is secured to the block 410 by bolts 504, these engaging in threaded recesses 505. In this construction I illustrate two reservoir chambers 506 and 501 dened by preferably an internal cylinder 508 extending downwardly from the head 502. This converges inwardly as indicated at 509 and is connected at the bottom 5|0 to the lower head 503. A transverse vertical partition 5|| connects both the heads and thus forms two reservoirs substantially semi-circular in cross section. This construction provides a longitudinal space or passage 5|2 between the lower and upper heads outside of the internal cylinder 508. 'I'his may have strengthening ribs connecting with the outside cylindrical wall 50| if desired, however it provides a large passage for the upfiow of the well liquid. The upper head is provided with four perforations 5|3 through each of which extends a connecting pipe 5|4 secured to the block 410 and each connected to a ,port 413, 414, 415 and 416. The upper portion of each of the reservoirs 506 and 501 is for a clean liquid such as a clean oil which is pumped through the mechanical pump 465 and transferred from one reservoir to another. The head 502 is provided with a series of passage perforations 5|5 which register with the passages 480 for the upward flow of Well liquid.

The chamber structure for the liquid piston designated by the assembly numeral 520 employs a cylinder 52| preferably of the same diameter as the cylinders 450 and 50|. This has an outlet valve block 522 at the top and is secured to the lower head 503 by bolts 523.

A diametrical wall or partition` 524 is preferably formed integral with the block 522 and extends downwardly, being connected to diametrically opposite sides of the cylinder 52|. This .partition has a lower section 525 reduced in thickness, thus providing two transverse shoulders 526. A lower or closure head 521 is formed of two substantially semi-circular plates 528 and 529 fitted inside of the lower end of the cylinde'r 52| and engaging the narrow section 525 of the partition 524 and abutting the shoulders 525 and is secured in place bylwelding indicated at 530 and 53|. This structure thus gms two pumping chambers designated 535 and The bottom head 503 of the reservoir assembly 500 has two outlet openings 540 and 54|, each having a pipe indicated. at 542 and 543 extending downwardly, the lower ends terminating as indicated at 544 spaced above the lower head 521. 'Ihese pipes are shown as secured by wells to the lower head 503 and pass through long perforations 545 in the outlet valve block 522.

A float valve assembly 546 is provided by a ball plug 541, a rod 548 and oat 549. The rod has a lower extension 550 extending downwardly in each of the tubes 542 and 543. form a plug at the valve seat formed by the peroilaations 540 and 54| or the upper ends of the u es.

An outlet valve assembly 555 includes a recessed passageway 556. For a two chamber construction there is an outlet valve from each chamber having a cage 551 threaded in the upper part of the recess, such cage passing through a perforation 558 in the lower head 503 and at the bottom has a check valve seat 559 engaged by a ball plug 560. A pin 56| retains the ball in the cage. This provides a check valve for the upilow of the well liquid but prevents a reverse or downward flow.

Into each chamber 553 and 556 there is an inlet valve assembly 510. This is made up by providing a circular recess 51| in each of the semi-` circular plates 528 and 529 fitting an internally threaded ring 512 in each recess. An inlet pipe 513 threaded to each ring extends upwardly through an opening 514 in each segmental plate.

A check valvg assembly 515 is provided at the The balls thus top of each pipe. This may be of any suitable character such as by having a cage, a seat and a ball confined within the cage. To secure the lrings 512 in place and retain the pipes 513 in proper position and also make a tight-seal, I preferably employ a bottom cover plate 516 bolted to the lower head 521 having openings 511 for the inflow of the well liquid. In the chamber 535 -and 536 I preferably insert before assembly a thin metal shell designated 580. This shell has openings at the top for the pipes and for the outlet ports or passages. Such shell is plated preferably with silver especially over the area contacted by mercury and the well liquid. It is also desirable to have a thin shell or the plating on the surface of the reservoirs 506 and 501 especiallyon the area where there is a contact between the mercury and the clean oil.

The manner of operation and functioning of the pumping assembly of Figs. 17 through 20 is substantially as follows: the piston liquid is indicated at 585 in the lower part of the chambers 535 and 536. This lls upwardly in the tubes 543 forming two vertical columns 586. The mercury also occupies the lower portion of reservoirs 506 and 501, being indicated at 581. The clean oil or other similar liquid activated by the mechanical pump is indicated at 588 in the upper part of the reservoirs 506 and 5.01 and communicates through the pipes 5|4 to the rotary valve 485 owing through the fixed ports 413, 414, 415 and 416 and the segmental slot ports 49| and 492 in the rotary ring part of the valve.

Presuming the valve to be rotating in the direction of the arrow 580, Figs. 19 and 20, in one position of the valve the clean oil is being pumped upwardly from one of the reservoirs, presuming this to be the reservoir 501 and discharged downwardly in the reservoir 506. This displaces downwardly the mercury body 581 in the reservoirs giving a downward ow to the column 586 and raising the mercury level in the chamber 535. Thus this action depletes the mercury in the reservoir 506 and also depletes the.volume in the chamber 536 and increases this in the reservoir 501. Such action therefore causes an inflow of the well liquid into the chambers 535 and 536. As depicted in Fig. 18, it is presumed that such liquid is owing inwardly in the chamber 536 and being forced out from the chamber 535. The alternate action therefore causes a transfer of the clean oil between the reservoirs 506 and 501, the transfer of mercury between, for instance, the reservoir 506 and the chamber 535 and the reservoir 501 and the charnber 536, thus giving alternate upward displacement to the well liquid, such as well oil, which after passing the check valve assembly 555 flows up in the space 512 through the perforations and passages I5 and 480, the space 559 and upwardly past the motor assembly and thence to the top of theI well in any suitable manner. It will be seen by this construction that there is no opportunity for the mercury to come into contact with the pump but the clean oil is always undergoing a pumping flow.- Should the mercury in either reservoir 506 or 501 become depleted below a desired amount, the float valve.-

of such chamber will close. 'This prevents out- Iiow of mercury from such chamber but the clean oil may be transferred from one chamber to another, thus allowing a release of pressure on the mercury in the depleted chamber and a raising of its elevation. The action however of the float valve and the flow of clean oil is somewhat diierent than from the construction of Figs. l and 2 for in the construction of Fig. 16 and Figs. 17 and 18, the liquid piston, that is, the mercury, flows between a reservoir and an associated pumping chamber by means of a column including a pipe. 'I'his mercury has an up and down ow, there being a pair of reservoirs thus connected to a pair of pumping chambers. The clean liquid acting on the mercury in the reservoir ows through the rotary valve, and through the pump from one reservoir to another. Therefore as the mercury becomes depleted in one reservoirgto such an extent that the float valve in such reservoir closes, it shuts 01T the mercury in such reservoir. In this case the clean liquid in the reservoir is considered to be in excess of that required for the proper operation of the pump so that such clean liquid is pumped from a reservoir having the excess to the other reservoir which is depleted of the clean liquid by having a surplus of mercury. This action relieves the pressure of the clean liquid in the reservoir depleted of mercury by its transference to the other reservoir and thus allows mercury to be forced upwardly from the pumping chamber connected to the reservoir depleted of mercury, raising the level and at the same time lifting the oat valve.

In the structures using both a chamberland reservoir for the mercury, with a connecting tube, it will be understood that my invention comprehends utilizing a long tube functioning as the reservoir. This makes a satisfactory construction where the pump assembly is quite long. The clean liquid may thenoccupy part of the tube and ow through the control valve and pump to and from one tube. In casesin which the pump is above the tubes and -the clean oil,`

the mercln'y float valvemay be installed in the long tube by providing a `proper seat.

Various changes may be madein the details of the construction without departing from the spirit or scope of the invention asdened by the appended claims.

I claim:

1. In a deep well pumping unit, the combina? the mechanical pump by a connection to the shaft, now ports and passages from each or the chambers to the valve, ports and passages connecting the valve to the mechanical pump where- -by on operation of the pump and the valve the uid is pumped from one chamber to another chamber, inlet means for well liquid to the fluid piston chambers including passages and a valved inlet to each chamber, a valved outlet from each chamber for the well liquid and means to conduct the ow of well liquid to the top of the well whereby, on operation of the pump and the valve, the :duid piston ows from one chamber causing an intake of. well liquid therein and ows into another chamber causing upward displacement of well liquid from such a latter chamber.

2. In a deep well pumping unit, the combination of a deep Well pump structure having two chambers for the liquid to be pumped in the well with a valved inlet and outlet means to and from said chambers for the ow of the well liquid, a reservoir connected to each chamber, a uid in each chamber and reservoir insoluble in the liquid to be pumped, a pumping means, a clean liquid in each reservoir in contact with the said :duid and means to operate the pump with a control means for causing a ow of the clean liquid to and from each reservoir and thereby causing a flow of thefluid to and from each reservoir and its associated chamber, such uid being operative as a fluid piston to develop a iiow ofthe well liquid through the said chambers.

3. In a device as described, the' combination of a deep well pump structure having two chambers with inlet and outlet control means for the well liquid to be pumped, a reservoir for each lchamber and connected by a conduit, a fluid in each reservoir and connecting through a conduit to its associated chamber, such.` uid being insoluble in the liquid to be pumped, a control valve, means to operate said valve, a clean liquid in each reservoir, passages connecting each reservoir and the valve, a pump, means to operate the pump in synchronism with the valve, connections between the pump and the valve for the flow of the clean liquid from one reservoir to another to thereby displace the said uid from each reservoir to a chamber and to develop a reverse ow of the uid from each chamber to its reservoir whereby a flow of the wellliquid is developed through each chamber, the said fluid geing operative as a liquid piston in each cham- 4. In a deep well pumping unit as claimed in claim 3, an outowing oat valve in each reservoir and operative on depletion of the said fluid in a particular reservoir to prevent the flow thereof, the said Valve and passages forming a connection whereby the clean `liquid may be transferred from a reservoir depleted of the fluid A to another reservoir and thus'relieve the pressure on the uid for replenishing the fluid in such reservoir from its connected chamber.

5. In a deep well pumping unit, the combination of a structure constructed and adapted to be lowered in a well andincluding a reservoir for a fluid piston and an inert gas, a pumping chamber with valved inlet and outlet for well liquid to be pumped, a mechanical pump and mechanical valve :to pump at least part of the fluid piston in veach cycle of operation from the reservoir to the lpumping chamber for displacement of well liquid, said pump and valve having passagev for transfer of at least part of thei :fluid piston in' each cycle of operation from the pumping chamber to the reservoir for inflow of well liquid to said pumping chamber.

6. In a deep well pumping unit, the combination of a deep well pump structure having two chambers with a valved inlet and outlet for each ,chamber for the well liquid to be pumped, each chamber being adapted to contain in its lower portion a iiuid piston, a fluid piston reservoir for each chamber with an up and down flow connection between a first reservoir and a rst chamber and a second chamber and a second reservoir, the chambers and reservoirs being located at different elevations, means to positively force theliquid piston out of a first chamber to a iirst reservoir and from a second reservoir to a second chamber and thereby develop an intake of well liquid into the rst chamber and a displacement oi the well liquid from the second chamber, the iluid piston comprising a first fluid of a heavy specific gravity and a second fluid of a lesser specific gravity, the flow means including a pump and valve operating on the second uid and having connections for transferring the second fluid between the two reservoirs.

7. In a deep well pumping unit the combination of a deep well pump structure having a rst and a second chamber withl a valved inlet and outlet for well liquid to be pumped, each chamber being adapted to receive and contain a fluid piston, a rst and a second reservoir positioned above the chambers with a flow connection from the ilrst reservoir to the rst chamber and from the second reservoir to the second chamber each having its discharge adjacent the bottom of the respective chambers, the reservoirs being adapted to contain a portion of the fluid piston, means to vary the hydraulic head of the fluid piston in each of the reservoirs and hence change the height of the uid piston in the said chambers in an alternating manner and thereby\develop an intake of well liquid into one chamber while the well liquid is being displaced from the other chamber.

8. In a deep well pumping unit the combination of a deep well pump structure having a rst and a second chamber with a valved vinlet and outlet for well liquid to be pumped, each chamber being adapted to receive and contain a iluid piston, a first and a second reservoir positioned xabove the chambers with a flow connection from therst reservoir to the first chamber and from the second reservoir to the second chamber each having its discharge adjacent the bottom'of the respective chambers,the reservoirs being adapted to contain a portion of the uid piston, means to vary the hydraulic head ofthe fluid piston in each of the reservoirs and hence change the height of the huid piston in the said chambers in an alternating manner and thereby develop an intake of well liquid into one chamber while the well liquid is being displaced from the other chamber, the fluid piston including a rst fluid of a. heavy specific gravity and a second uid of a lesser specific gravity in the reservoirs, the means to change Ythe head of the fluid piston in the reservoir including a pumping means to positively transfer the second fluid between the two reservoirs.

tween each of the upper to its corresponding lower compartment, a float valve in each of the upper compartments controlling the depletion of the heavy fluid piston from the upper compartments, one pair of the compartments having means for controlling the ilow of\ well liquid therethrough, a pump with connections to transfer the light liquid piston between the two com- Y compartments to thereby open the float valve 9. In a deep welllpmping unit, the combina- Y.

of the depleted compartment for flow of the heavy fluid piston thereinA 10. In a deep well pumping unit having two pumping chambers each with a valved inlet and outlet for well oil to be pumped, each chamber being adapted to contain a liquid piston, each chamber having an inlet port and an outlet float valve for the liquid piston, a positively driven pump with a valve and flow connections for the liquid piston to transfer the liquid piston between the said chambers, such liquid piston passing out through the float valve in one chamber and into the other chamber through its inlet port, the said valve having connections whereby if the liquid piston is depleted below a working level in one chamber by the outlet float valve of such chamber being closed, the liquid piston is pumped from the chamber having the excess of the liquid piston to the depleted chamber through the inlet port of the depleted chamber.

11. In a deep well pumping unit, the combination of a deep well pump structure having two chambers for a fluid piston and at least one of said chambers being for the well liquid to be pumped wit-h valved inlet and outlets for the well liquid chamber, each chamber containing a fluid piston, a power driven means to' positively vflow the iluid piston with an up and down mo-V tion from one chamber to the other to thereby cause an intake of the well liquid into the well liquid chamber and a displacement therefrom, each of the chambers having anv inlet p ort and a valve outlet forI the fluid piston, the power driven means having associated therewith and with each of the valved outlets for the fluid piston means for directing the flow of such piston to prevent depletion of the liquid piston in either of the chambers below a working level.

f .12. In a deep well pumping unit, a structure arranged to be lowered into a well having a chamber provided to receive liquid to be pumped, valved inlet and outlet to said chamber for such liquid, a reservoir, a. circulating fluid insoluble in the liquid to be pumped retained in said chamber and reservoir to act as a piston on said liquid, a circulating pump. a rotary iiow control valve, passageways connecting the iluid in said chamber and reservoir to the circulating pump through the rotary lflow control valve causing said iluid in said liquid chamber and reservoir to flow in and out of said chamber and reservoir thereby drawing in liquid to be pumped and/or discharging liquid from said chamber to 'produce a pumping action in the liquid to be pumped, and a motor. associated with said unit connected" to operate said circulating pump.

13. In adeep well pumping unit, a structure y fluid piston.

provided to be lowered in a well having two chambers for a liquid to be pumped, valved inlet and outlet to said chambers for a flow of liquid to be pumped, a circulating fluid insoluble in the liquid to be pumped in said chambers acting as a piston on said liquid, an actuating means in- 'clu'ding a pump for said fluid, a flow control valve interposed between said chamber and the said pump, passageways connecting the uid in said chambers to said valve and to said pump, the

surface finish of said chambers and the characteristics of said fluid being such as to prevent sticky or gritty material adhering to said surface nish, a motor having a connection to operate the pump and the valve thereby causing such uid to flow in or out of said chambers and hence cause an inflow and/or a discharge flow of liquid to be pumped to and/or from said chambers, means to stop the outflow of fluid from said chambers to'thereby prevent depletion and a control through the valve and passages to replenish the fluid in a partially depleted chamber.

14. In a deep well pumping unithaving two valved chambers with a liquid piston therein, a positively driven pump and flow means interconnecting the chambers for causing the liquid piston to rise or fall in said valved chambers, the said pump and flow means having connections at certain positions of their operations to supply part of a fluid piston from a chamber having an excess to a chamber having a depletion of fluid piston to maintain a, working level of the fluid piston at all times in the chambers, said pumping unit including valved means to pump well liquid by the rise and fall of the 15. In a deep well submersible pumping unit, the combination of a deep well pump structure having two chambers with a valved inlet and outlet for each chamber for the well liquid to be pumped, each chamber being adapted to contain in its lower portion a fluid piston, a fluid piston reservoir for each chamber with an up and down flow connection between a rst reservoir and a rst chamber and a second chamber and a second reservoir, a flow connection between the two reservoirs, the chambers and reservoirs being located at different elevations, means to positively now liquid between the reservoirs and force the liquid piston out of a first chamber to a first reservoir and from a second reservoir to a second chamber and thereby develop an intake of well -liquid into the first chamber and a. displacement of the well liquid from the second chamber.

16. In a. deep well submersible pumping unit, a structure having a chamber provided to receive well liquid to be pumped, valved inlet and outlet to said chamber for such well liquid, a. reservoir, a circulation fluid insoluble in the well liquid to be pumped in said chamber or reservoir acting as a piston on said well liquid, an actu ating means for said fluid, a change of direction flow means for the fluid, passageways connecting to the fluid insaid chamber and reservoir to the actuating means causing said fluid in said liquid chamber and reservoirto flow in and out of said chamber and reservoir thereby drawing in liquid to be pumped and/or discharging such liquid from said chamber, and a submerged motor directly associated with said unit connected to operate said actuating means.

17. In a deep well submersible pumping unit, a structure having a chamber provided to receive well liquid to be pumped, valved inlet and outlet to said chamber for such well liquid, a reservoir, a circulation uid insoluble in the liquid to be pumped partially retained in said chamber and reservoir to act as a piston on said well liquid, a pressure and/or suction means for such fluid, passageways connecting the fluid in said chamber and reservoir to the pressure and/or suction creatingmeans causing said fluid in said liquid chamber and reservoir to flow in and out of said chamber and reservoir thereby drawing in theA well liquid and/or discharging the well liquid to be pumped from said chamber, and' a valvel opening and/or closing the passageways through which the fluid acted on by said pressure and/or suction is to move, and a submerged motor directly associated with said pumping unit connected to operate said pressure and/or suction means and the valve.

18. In a deep Well submersible pumping unit.

the combination o`f a deep well pump structure having means for lowering the same and supporting in a deep well, said structure having a mechanical pump, two chambers for a fluid piston. a control valve connecting said chambers and the mechanical pump to control the flow of fluid piston between the chambers and the pump, means to actuate the mechanical pump and means to actuate the valve in synchronism therewith, ports and passages for a fluid communicating between said chambers and the mechanical pump for pumping a fluid from a chamber through the mechanical pump to the other chamber and hence flow the fluid piston in and out of the two chambers, a well liquid connection from the well'to the chambers containing the fluid piston, a valved inlet and outlet for the well liquid in itsyflow from and to said chambers, and a flow connection' for the Well liquid to the top of the well whereby on operation of the mechanical pump and the said valve, fluid piston fluid is' .withdrawn from one chamber for intake of well liquid therein and fluid piston fluid flows to another chamber for displacement of well liquid upwardly.

19. Ina deep well submersible pumping unit, a pump structure arranged to be lowered into a well having a well liquid chamber with means for in and out flow of Well liquid, a pump, a valve,a receptacle, ports and passages communicating between thechamber and the receptacle, the pump and the valve, the said chamber having mercury therein operating as a fluid piston in the well liquid, the pump and valve being adapted to flow the mercury in and out of said chamber and receptacle, the said chamber having a silver plated surface whereby the mercury cleans such surface of any oil or grit accumulating from' the well oil on such surface.

20. In a deep well submersible pumping unit, a pump structure arranged to be lowered into a well having a well liquid chamber with means for in and out flow ofv well liquid, a pump, a valve, a receptacle, ports and passages-communicating between the chamber and the receptacle, the pump and the valve, the said chamber having mercury therein operating as a fluid piston in the well liquid, the pump and valve being adapted to ow the mercury in and out of said chamber and receptacle, the said chamber having an inserted lining susceptible to amalgamation whereby the mercury cleans the lining of any oil or grit accumulating from the well oil on such lining.

21. In a deep well submersible pumping unit,

the combination of a deep well pump structure having two chambers for a fluid piston and at least one of said chambers being for the well liquid to be pumped with valved inlet and outlets for the well liquid chamber, each chamber containing a fluid piston, a fluid piston circulating means, a submerged motor directly connected to said iluid piston circulating means to positively 'ilow the fluid piston from one chmber to the other to thereby cause an intake of the well liquid into the well liquid chamber and a displacement therefrom.

22.. A pump comprising containing means, a liquid piston therein, means for moving the liquid piston to and fro therein, a gas between the piston and one end of the container means adapted to be compressed by the piston when the piston is forced toward said end and to assist in forcing the piston in the opposite direction, there being an inlet and outlet to and from the containing means for the iluid to be pumped on the opposite side of the-piston from said gas and means for preventing reverse iiow thru the inlet and outlet respectively.

23. A pump comprising means providing a lcontaining means having an inlet and an outlet for the duid to be pumped, means for preventing reverse ilow thru the inlet and outlet respectively, a liquid piston in the containing means, a gas conlned in the containing means against the piston and means for moving the liquid piston back and forth in the containing means whereby when the piston is moved in one direction, fluid to be pumped will be drawn into the containing means thru the inlet and the gas will be compressed by the piston and when the piston is moved in the opposite direction the iluid to be pumped will be expelled thru the outlet and the compressed gas will assist in forcing the piston in said opposite direction.

24. A pump comprising means containing a liquid piston and a gas confined against one side thereof, there being an inlet and an outlet` for the fluid to be pumped arranged on the other side of said piston, means for preventing reverseflow thru the inlet and outlet and means for moving the liquid piston back and forth in the containing means whereby when the liquid piston is moved in one` direction fluid to be pumped will be drawn into the containing means thru the inlet and the gas will be compressed, and when the piston is moved in the other direction the compressed gas' will aid such movement and the fluid to be pumped will be expelled thru the flow connection from the iirst reservoir to the rst chamber and from the second reservoir to the second chamber, each flow connection having well liquid, means to pump lsuch circulating liquid from one reservoir to another and to vary the hydraulic head of the fluid piston in each of the reservoirs and hence change the height of the fluid piston in the said chambers in an alternating manner and thereby develop an intake of well liquid into one chamber while the well liquid is being discharged from -the other chamber.

26.7In a deep well self contained submersible motor driven pumping unit, a pump structure having means for lowering and supporting such unit in a deep well and including a fluid piston chamber, a reservoir and a mechanical pump for circulating an entrapped iluid between the chamber, the mechanical pump and the reservoir, means to operate said mechanical pump, there being connections between the said chamber and reservoir and mechanical pump for the entrapped iluid to circulate a fluid piston from and to said chamber and reservoir, an inlet means for well liquid to said chamber and a valve controlled outlet means for the well liquid from such chamber for the flow of the well liquid to the top of the well whereby, on operation of the mechanical pump, lrhe iiuid piston displaces the well liquid forcing it upwardly in the well.

27. In a submersible motor driven oil well pumping unit, the combination of a pump structure having two pump'chambers with a valved its discharge adjacent the bottom of the respective chambers and additional flow connections between the reservoirs, the reservoirs being adapted to contain a portion of the liquid piston and pump circulating liquid separate from the inlet and outlet for each chamber for the well liquid to be pumped, each chamber being adapted to contain a fluid piston, two reservoirs also for fluid piston independent of and separate from the well liquid, flow connections between the reservoirs, means to positively force fluid under pressure from one reservoir to the .other and to ilow the iluid piston alternately from a rst chamber to a iirst reservoir. to decrease the iluid piston in' such rst chamber and increase the iiuid piston in the first reservoir, and from a second reservoir to a second chamber to increase the iluid piston in the second chamber and decrease the fluid piston 'in the second reservoir and thereby develop an intake of well liquid into the iirst chamber and a displacement of the well liquid from the second chamber.

28. In an oil well submersible motor pumping unit, the combination-of a pump structure having two pump chambers with a valved inlet and outlet for each chamber for the well liquid to be pumped, each chamber being adapted to contain a iluid piston, two reservoirs also for iluid piston. flow connections between the reservoirs, and means independent and separate from the well liquid to positively force the fluid piston alternately from one reservoir toanotlier to flow the uid piston from a flrst chamber to a first reservoir to decrease the fluid piston in such rst chamber and increase the fluid pistn in the first reservoir and from a second reservoir to a second chamber `to increase the fluid piston in the second chamber and decrease the iluid piston in the second reservoir and thereby develop an intake of well liquid into the rst chamber and a displacement of the well liquid in the second chamber, the means to flow the fluid piston from each reservoir to its Ycorrespondingchamber includ- 

